US6049520A - Drive mechanism for rotating storage media - Google Patents
Drive mechanism for rotating storage media Download PDFInfo
- Publication number
- US6049520A US6049520A US09/000,688 US68897A US6049520A US 6049520 A US6049520 A US 6049520A US 68897 A US68897 A US 68897A US 6049520 A US6049520 A US 6049520A
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- United States
- Prior art keywords
- data storage
- storage medium
- magnetic
- elements
- drive mechanism
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/20—Driving; Starting; Stopping; Control thereof
Definitions
- the present invention relates generally to mechanisms for rotating data storage media, and more specifically relates to a drive mechanism for positioning, rotating and centering a two-sided data storage medium.
- Devices for reading data from a data storage disc such as a CD-ROM drive for reading data from a CD-ROM, are typically designed such that the data storage disc is first placed in a disc caddy or a sliding tray. After the data storage disc is so placed, the disc caddy or sliding tray conveys the data storage disc to a driving mechanism and continues to support the data storage disc until the driving mechanism begins rotating the data storage disc at which time data is read from the data storage disc.
- a typical driving mechanism for driving the rotation of the data storage disc includes a motor-driven chuck and spindle assembly where the chuck holds the data storage disc by retaining a center hole in the data storage disc. After the chuck has retained the data storage disc using the center hole, the chuck and spindle assembly rotate thereby causing rotation of the data storage disc.
- a data head capable of reading from the disc is positioned along a radius to read data from data tracks on the data storage disc, and a focus actuator in communication with the data reading head continuously adjusts the distance between the data reading head and the data storage disc so that the data reading head remains focused on the data and can successfully read the data from the data storage disc even if the data storage disc is not rotating perfectly.
- the above-described data reading device, and driving mechanism thereof has several disadvantages.
- the spindle and chuck assembly, as well as the motor to drive same must be positioned either above or below the data storage disc so that the data storage disc can be engaged by the chuck and rotated.
- This arrangement limits the minimum height to which the data reading device can be minimized. It is often desirable to minimize the area occupied by a data reading device because, among other reasons, such devices are presently widely used in portable computer applications.
- the center hole of the data storage disc, and the data storage disc itself necessarily have design tolerances and these design tolerances can hinder the efficient operation of the data reading device.
- an imperfect center hole can cause the data storage disc to periodically vibrate as the data storage disc is rotated by the chuck and spindle assembly of the drive mechanism. Such vibration causes the data reading head to oscillate along the sled as it works to follow a specific data track. If the vibration of the data storage disc is adequately severe, the vibration can cause the data reading head to fail to follow the specific data track.
- the data storage disc if the data storage disc is chucked at even only a slight angle relative to the plane of the data reading head, the data storage disc will tend to oscillate above the head as it rotates. Such an oscillation will cause the focus actuator to also oscillate as it works to keep the data reading head focused on the data. If the oscillation of the data storage disc is adequately severe, the oscillation of the data storage disc can prevent the focus actuator from maintaining the head focused on the data.
- the data reading device necessitates initial physical contact of the data storage disc with either a disc caddy or a sliding tray, and subsequent physical contact of the data storage disc with a chuck. Physical contact with the data storage disc can cause the data storage disc to become scratched or otherwise damaged and cause some of the data stored on the data storage disc to become inaccessible.
- the present invention provides a novel drive mechanism which alleviates the problems discussed above.
- an object of the present invention is to provide a drive mechanism which decreases the area required to be occupied by a data reading (or writing) device.
- Another object of the present invention is to provide a drive mechanism which can accommodate design tolerances of a data storage disc.
- a further object of the present invention is to provide a drive mechanism which can position a data storage disc for subsequent rotation without requiring physical contact therewith.
- a still further object of the present invention is to provide a drive mechanism which can rotate a data storage disc without requiring physical contact therewith.
- the present invention provides a drive mechanism in a data storage apparatus for positioning and rotating a two-sided data storage medium having a least one control element thereon.
- the data storage medium is a two-sided, removable data storage disc.
- the drive mechanism includes two pairs of magnetic bearings, and each pair of magnetic bearings is adjacent a respective side of the data storage medium so that the data storage medium is held in position by the magnetic forces applied by the magnetic bearings to at least one control element.
- the magnetic forces applied by the magnetic bearings are repelling forces.
- the magnetic bearings may instead apply attractive forces. Any suitable magnetic or non-magnetic repeller or attracter may be used to apply either a repelling or attractive force to the data storage medium.
- the drive mechanism also includes a plurality of driver elements adjacent the data storage medium.
- a plurality of stationary electromagnetic driver elements are adjacent the circumference of the data storage disc, and each of the stationary electromagnetic driver elements is capable of selectably attracting or repelling the at least one control element on the data storage medium thereby causing the data storage medium to rotate while the date storage medium is positioned by the one or more magnetic bearings and is substantially centered by at least two of the electromagnetic driver elements.
- the magnetic band on the data storage disc includes a plurality of spaced-apart concentrated permanent magnetic elements, and the electromagnetic driver elements are spaced-apart from each other in a spacing arrangement different from that of the concentrated permanent magnetic elements of the magnetic band on the data storage disc.
- the at least one magnetic bearing element adjacent each side of the data storage disc exerts opposing forces on the concentrated permanent magnetic elements of the magnetic band on the data storage disc thereby creating a magnetic bearing on which the data storage disc can move and rotate.
- the electromagnetic driver elements are preferably controlled by a variable electric current such that the magnetic field generated by the electromagnetic driver elements can be modulated to cause the data storage disc to rotate.
- At least one of the electromagnetic driver elements is positioned and is chargeable for attracting at least one of the concentrated permanent magnetic elements of the magnetic band on the data storage disc such that the data storage disc can be magnetically pulled substantially into a pre-determined position for rotation thereof.
- at least one of the electromagnetic driver elements is positioned and is chargeable for attracting at least one of the concentrated permanent magnetic elements of the magnetic band on the data storage disc such that the data storage disc can be magnetically braked and the rotation thereof limited.
- at least one of the electromagnetic driver elements is positioned and is chargeable for repelling at least one of the concentrated permanent magnetic elements of the magnetic band on the data storage disc such that the data storage disc can be magnetically pushed from the pre-determined position.
- the present invention may include a method of positioning and rotating a two-sided data storage medium by applying a magnetic force to at least one control element on the data storage medium thereby positioning the storage medium substantially in a pre-determined position for rotating the data storage medium, and selectably attracting and/or repelling the at least one control element on the data storage medium thereby causing the data storage medium to rotate while the data storage medium is substantially maintained in the pre-determined position.
- the at least one control element on the data storage medium includes a plurality of permanent magnetic elements spaced-apart from each other in a spacing arrangement different from that of the permanent magnetic elements on the data storage medium; and the method further includes charging at least one of the electromagnetic elements to attract at least one of the permanent magnetic elements on the data storage medium such that the data storage medium is magnetically pulled substantially into a pre-determined position for rotation thereof.
- variable electric currents are used to control a plurality of electromagnetic driver elements located adjacent the data storage medium such that the magnetic fields generated by the electromagnetic driver elements can be modulated to cause the data storage medium to rotate.
- the method further may also include charging at least one of the electromagnetic elements to attract at least one of the permanent magnetic elements on the data storage medium such that the data storage medium is magnetically braked and the rotation thereof limited, and includes charging at least one of the electromagnetic elements to repel at least one of the permanent magnetic elements on the data storage medium such that the data storage medium is magnetically pushed from the pre-determined position.
- FIG. 1 is a perspective view, schematic in nature, of a data storage apparatus, illustrating a housing thereof in phantom and a drive mechanism in accordance with a preferred embodiment of the present invention within the housing;
- FIG. 2a is a top, plan view of the data storage apparatus of FIG. 1, illustrating with arrows the drive mechanism receiving a removable disc storage medium;
- FIG. 2b is a side, elevational view of the data storage apparatus of FIG. 1, illustrating with arrows the drive mechanism receiving a removable disc storage medium;
- FIG. 3a is a top, plan view, similar to FIG. 2a, of the data storage apparatus of FIG. 1, illustrating the removable disc storage medium fully received by the drive mechanism;
- FIG. 3b is a side, elevational view, similar to FIG. 2b, of the data storage apparatus of FIG. 1, illustrating the removable disc storage medium fully received by the drive mechanism;
- FIG. 3c is a front, elevational view of the data storage apparatus of FIG. 1, illustrating the removable disc storage medium fully received by the drive mechanism;
- FIG. 4 is a top, plan view, similar to FIGS. 2a and 3a, of the data storage apparatus of FIG. 1, wherein the top permanent magnetic bearings are omitted for clarity, and illustrating with arrows the drive mechanism rotating the removable disc storage medium;
- FIG. 5 is another top, plan view, similar to FIGS. 2a, 3a and 4, of the data storage apparatus of FIG. 1, wherein all the permanent magnetic bearings are omitted for clarity, and illustrating with arrows the drive mechanism rotating the removable disc storage medium at a different point in time than is depicted in FIG. 4;
- FIG. 6 is yet another top, plan view, similar to FIGS. 2a, 3a, 4 and 5, of the data to storage apparatus of FIG. 1, wherein all the permanent magnetic bearings are omitted for clarity, and illustrating with arrows the drive mechanism rotating the removable disc storage medium at a different point in time than is depicted in FIGS. 4 and 5;
- FIG. 7 is a top, plan view, similar to FIGS. 2a, 3a and 4-6, of the data storage apparatus of FIG. 1, wherein all the permanent magnetic bearings are omitted for clarity, and illustrating the drive mechanism braking the rotation of the removable disc storage medium;
- FIG. 8 is a side, elevational view, similar to FIGS. 2b and 3b, of the data storage apparatus of FIG. 1, wherein all the permanent magnetic bearings are omitted for clarity, and illustrating with arrows the drive mechanism ejecting the removable disc storage medium.
- FIGS. 1-8 illustrate a data storage apparatus 10 including a drive mechanism 12 in accordance with a preferred embodiment of the present invention.
- the data storage apparatus 10 preferably includes a housing 14 that defines an opening to 16, and a door 18 for covering the opening 16.
- the door 18 is adapted to open so that a data storage medium 20, such as a removable data storage disc 22, can be inserted into the housing 14 and brought into engagement with the drive mechanism 12 inside the housing 14, as illustrated, for example, by FIGS. 2a-8.
- a sensor 58 in the housing 14 for sensing when a data storage disc 22 is inserted through the door 18.
- the sensor 58 may, for example, comprise one or more diodes which optically detect that a data storage disc 22 is being inserted into the data storage apparatus 10.
- the sensor 58 may be some type of magnetic sensor which senses the magnetic band of the data storage disc 22.
- the data storage disc 22 is rotated while a data reader (not shown) reads data from (or while a data writer writes data to) the data storage disc 22.
- the data reader may be in any suitable form, such as, for example, a conventional sled/head assembly.
- the data storage apparatus 10 in an alternative embodiment may instead use a non-removable data storage medium and does not require the door 18.
- the data storage apparatus 10 may be a rigid, magnetic disc drive.
- the data storage disc 22 desirably includes a control element 24.
- the control element 24 is a magnetic band 26 around the circumference of the data storage disc 22 that includes permanent magnetic material 28 throughout and has relatively stronger, evenly spaced-apart, permanent magnetic portions, or point elements 30.
- the magnetic band may include any suitable number of point elements 30 and any suitable spacing therebetween, depending on the specific application in which the present invention is used. Therefore, while a certain number of point elements 30 and spacing therebetween is depicted in the drawings, the invention, of course, is not so limited.
- the magnetic band 26 can be provided already manufactured into the data storage disc 22, or may be applied at a later time by, for example, the consumer. In this case, it is envisioned that the magnetic band 26 may be applied by the consumer directly to the circumferential edge of any of the presently widely commercially available CD-Rom's, music CD's or DVD discs for use with the drive mechanism 12 in accordance with the present invention.
- the drive mechanism 12 includes at least one magnetic means 32, such as a permanent magnetic bearing plate 34, located adjacent each side 36, 38 of the data storage disc 22 when the data storage disc 22 is engaged with the data storage apparatus 10.
- the drive mechanism 12 desirably also includes one pair 40 of opposing spaced-apart, parallel permanent magnetic bearing plates 34 adjacent the right side 42 of the housing 14, and includes another pair 44 of opposing spaced-apart, parallel permanent magnetic bearing plates 34 adjacent the left side 46 of the housing 14.
- each of the permanent magnetic bearing plates 34 is magnetized with the same magnetic polarity, and is of the same magnetic polarity as the point elements 30 of the magnetic band 26 on the data storage disc 22.
- each of the permanent magnetic bearing plates 34 apply a repelling force to the magnetic band 26 on the data storage disc 22.
- an alternative embodiment of the present invention may provide that each of the permanent magnetic bearing plates 34 is magnetized with the opposite magnetic polarity as the point elements 30 of the magnetic band 26 on the data storage disc 22. Therefore, each of the permanent magnetic bearing plates 34 would apply an attracting force to the magnetic band 26 on the data storage disc 22. It is also possible to provide for means other than magnets to attract or repel the magnetic storage disc 22.
- permanent magnetic bearing plates 34 may also be positioned in the housing 14 along the front 48 and rear 50 thereof; or one doughnut-shaped permanent magnetic bearing plate 34 may be provided over the data storage disc 22, and another may be provided under the data storage disc 22. Still further, one permanent magnet may be provided where the magnet is positioned adjacent one side of the data storage disc 22 and extends to adjacent the other side of the data storage disc 22. Hence, a single permanent magnetic bearing may be used to position the data storage disc 22.
- the data storage disc 22 When the data storage disc 22 is inserted into the opening 16 of the data storage apparatus as shown in FIGS. 2a and 2b, the data storage disc 22 is repelled by the permanent magnetic bearing plates 34 and is urged into a substantially level position between each pair 40 and 44 of permanent magnetic bearing plates 34.
- the permanent magnetic bearing plates 34 exert opposing forces on the magnetic band 26 and prevent the data storage disc 22 from contacting any internal structure of the data storage apparatus 10.
- the permanent magnetic bearing plates 34 magnetically suspend the data storage disc 22 on a magnetic bearing between each pair 40 and 44 of the permanent magnetic bearing plates 34, and provide a nominally flat surface on which the data storage disc 22 can rotate.
- the permanent magnetic bearing plates 34 continue to exert opposing forces on the magnetic band 26 and therefore prevent the data storage disc 22 from contacting any internal structure of the data storage apparatus 10 as the data storage disc 22 is being ejected.
- the drive mechanism 12 in accordance with the present invention also includes a plurality of driver elements 52 located adjacent the data storage disc 20 when the data storage disc 20 is fully received by the data storage apparatus 10 as shown in FIGS. 3a-7.
- the driver elements 52 are spaced-apart, stationary electromagnetic driver elements 54 located around the perimeter of the fully received data storage disc 22, and are controlled by a variable electric current such that the magnetic field generated by the electromagnetic driver elements 54 can be modulated to cause the data storage disc 22 to rotate as described hereinafter.
- the data storage apparatus 10 may be provided with a plurality of electromagnetic driver current in lines 56 for supplying electric currents to the electromagnetic driver elements 54.
- driver elements 54 While the drawings depict four electromagnetic driver elements 54 positioned approximately ninety degrees apart from one another with one at each of the front 48, rear 50, right 42 and left 46 sides of the housing 14, the present invention is not limited to such a configuration. Rather, the number and positioning of driver elements 52 utilized will inevitably depend on the specific application in which the present invention is used. In fact, depending on the application, additional driver elements 52 may be needed in order to keep the data storage disc 22 substantially centered during rotation. Alternatively, if desired, some type of chuck or bearing insertable through a center hole of the data storage disc 22 may be utilized in order to keep the data storage disc 22 substantially centered.
- a removable data storage medium 20, such as a removable data storage disc 22 including the above-described magnetic band 26, is inserted through the door 18 into the opening 16 of the housing 14.
- each pair 40 and 44 of permanent magnetic bearing plates 34 exerts opposing forces to the permanent magnetic band 26 of the data storage disc 22.
- the sensor 58 in the data storage apparatus 10 senses that a data storage disc 22 is being inserted.
- the electromagnetic driver element 54 adjacent the rear 50 of the housing 14, opposite the opening 16 is controlled so as to exert an attractive magnetic force to the permanent magnetic band 26, and specifically one or more of the point elements 30 thereof, so that the data storage disc 22 is pulled into a pre-determined position for rotation, as shown in FIGS. 3a-3c.
- the data storage disc 22 is brought to a position substantially centered amongst the electromagnetic driver elements 54 and is suspended by the magnetic forces being applied by the permanent magnetic bearing plates 34.
- the permanent magnetic bearing plates 34 provide a substantially flat magnetic bearing surface on which the data storage disc 22 can rotate.
- the data storage disc 22 may be rotated and data read therefrom (or data written thereto). Rotation of the data storage disc 22 by the drive mechanism 22 will now be described.
- the electromagnetic driver elements 54 are controlled by a variable electric current such that the magnetic fields generated by the electromagnetic driver elements 54 are modulated. The modulation of the magnetic fields causes the data storage disc 22 to rotate.
- the angular velocity of the data storage disc 22 can be varied by modulating the strength of the magnetic forces applied to the data storage disc 22 by the electromagnetic driver elements 54.
- the number and spacing of the point elements 30 on the magnetic band 26 will be dictated by the specific application, it is preferable that the number of point element 30 and driver elements 52, and their angular relationship, be spaced differently such that the point elements 30 and driver elements 52 are not perfectly aligned, otherwise the data storage disc 22 may be loaded into the data storage apparatus 10 and not be able to be rotated by the driver elements 52, or may caused to rotate in the wrong direction.
- rotation of the data storage disc 22 may be initialized by, for example, controlling the electromagnetic driver element 54 adjacent the right side 42 of the housing 14 so that it creates a strong magnetic field equal to the polarity of the closest point element 30 of the magnetic band 26 on the data storage disc 22, thereby pushing this closest point element 30 to the left and imparting a counter-clockwise rotation of the data storage disc 22.
- the opposing electromagnetic driver element 54 adjacent the left side 46 of the housing 14 is controlled to create a magnetic field opposite of the polarity of the closest point element 30 of the magnetic band 26 thereby pulling this closest point element 30 to the right and further imparting a counter-clockwise rotation of the data storage disc 22.
- the other electromagnetic driver elements 54 adjacent the front 48 and rear 50 of the housing 14 are controlled so as to either emit no magnetic field or to emit a slight, equal polarity magnetic force in order to keep the data storage disc 22 centered during rotation.
- FIGS. 5 and 6 show further examples of the pushing and pulling of the point elements 30 of the magnetic band 26 of the data storage disc 22 by the electromagnetic driver elements 54.
- the electromagnetic driver elements 54 adjacent the left side 46 and the rear 50 of the housing 14 may be controlled to create magnetic fields opposite the polarity of the closest point elements 30, thereby pulling them and imparting a counter-clockwise rotation of the data storage disc 22.
- the electromagnetic driver elements 54 adjacent the front 48 and right side 42 of the housing 14 may be controlled to create magnetic fields having the same polarity of the closest point elements 30, thereby pushing them away and further imparting a counter-clockwise rotation of the data storage disc 22.
- the electromagnetic driver elements 54 adjacent the right side 42 and front 48 of the housing 14 ma be controlled to create magnetic fields having an opposite polarity than that of the closest point elements 30, thereby pulling them and imparting a counter-clockwise rotation of the data storage disc 22.
- the electromagnetic driver elements 54 adjacent the left side 46 and the rear 50 of the housing 14 may be controlled to create magnetic fields having the same polarity as the closest point elements 30 thereby pushing them away, and further imparting a counter-clockwise rotation of the data storage disc 22.
- rotation of the data storage disc 22 using the electromagnetic driver elements 54 can be accomplished by controlling the electromagnetic driver elements 54 in a manner different than as was described in reference to FIGS. 4-6. Regardless, the data storage disc 22 can be rotated using magnetic fields and without necessitating actual physical contact therewith using a driven chuck and spindle assembly.
- the data storage disc 22 may be "braked” to limit or stop the rotation, as illustrated by FIG. 7, and thereafter ejected from the data storage apparatus 10.
- the electromagnetic driver elements 54 can all be controlled to attract the point elements 30 on the magnetic band 26 of the data storage disc 22 and to directly align a point element 30 with the electromagnetic driver element 54 located adjacent the rear 50 of the housing 14, opposite the opening 16.
- the data storage disc 22 can be ejected from the data storage apparatus 10 as shown in FIG. 8.
- one way to eject the data storage disc 22 is to control the electromagnetic driver element 54 located adjacent the rear 50 of the housing 14, opposite the opening 16, so as to emit a magnetic field having a magnetic polarity equal to that of the aligned point element 30.
- the closest point element 30 is repelled, and the data storage disc 22 is essentially ejected from the data storage apparatus 10.
- the data storage disc 22 is ejected at least half-way so that a user can grasp the data storage disc 22 and entirely remove same from the data storage apparatus 10, out the opening 16.
- the data storage apparatus 10 in accordance with a preferred embodiment of the present invention provides for the receiving, rotating and ejecting of a data storage medium 20 using magnetic fields.
- the data storage medium 20 is less susceptible to damage
- the data storage apparatus 10 can more readily accommodate design tolerances of data storage media and maintain the efficient data reading therefrom or data writing thereto, and, if desired, a driven chuck and spindle assembly can be omitted from the data storage apparatus 10 thereby allowing for further minimization of the area occupied thereby.
- the present invention is well suited for use in association with optically-written and optically-read data storage media. While the present invention was described in association with a data storage apparatus 10 amounting essentially to a CD-ROM system, the invention was so described merely to convey the concepts of the invention, and the invention may be applied to other rotating data storage systems.
Abstract
Description
Claims (40)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US09/000,688 US6049520A (en) | 1997-12-30 | 1997-12-30 | Drive mechanism for rotating storage media |
Applications Claiming Priority (1)
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US09/000,688 US6049520A (en) | 1997-12-30 | 1997-12-30 | Drive mechanism for rotating storage media |
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US6049520A true US6049520A (en) | 2000-04-11 |
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US09/000,688 Expired - Lifetime US6049520A (en) | 1997-12-30 | 1997-12-30 | Drive mechanism for rotating storage media |
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Cited By (3)
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US20020074416A1 (en) * | 2000-12-14 | 2002-06-20 | Koninklijke Philips Electronics N.V. | Device for scanning an electromagnetically suspended information carrier |
US6570834B1 (en) * | 2000-11-01 | 2003-05-27 | Sony Corporation | Electromagnetic inductive drive and method of making the same |
US20030123340A1 (en) * | 2001-12-28 | 2003-07-03 | Jin-Chuan Wei | Magnetically suspended CD-ROM drive |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6570834B1 (en) * | 2000-11-01 | 2003-05-27 | Sony Corporation | Electromagnetic inductive drive and method of making the same |
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